A sintered MnZn ferrite body containing main components comprising 53.30-53.80% by mol of Fe calculated as Fe.sub.2O.sub.3, 6.90-9.50% by mol Zn calculated as ZnO, and the balance of Mn calculated as MnO, and sub-components comprising 0.003-0.020 parts by mass of Si calculated as SiO.sub.2, more than 0 parts and 0.35 parts or less by mass of Ca calculated as CaCO.sub.3, 0.30-0.50 parts by mass of Co calculated as Co.sub.3O.sub.4, 0.03-0.10 parts by mass of Zr calculated as ZrO.sub.2, and 0-0.05 parts by mass of Ta calculated as Ta.sub.2O.sub.5, pre 100 parts by mass in total of the main components (calculated as the oxides), and having an average crystal grain size of 3 μm or more and less than 8 μm and a density of 4.65 g/cm.sup.3 or more.

A method for manufacturing a powder magnetic core includes: a step of preparing a soft magnetic powder and an oxide powder and preparing, as a raw material powder, a mixed powder of the soft magnetic powder and the oxide powder, the soft magnetic powder containing composite soft magnetic particles containing pure iron and an Fe-α alloy having an element α more oxidizable than Fe, the composite soft magnetic particles each having a core-shell structure where a core is made of one of pure iron and the Fe-α alloy and a shell is made of the other, the oxide powder containing oxide particles containing at least one selected from Fe and an element β that forms an oxide having higher electrical resistance than Fe.sub.3O.sub.4; a step of compacting the mixed powder into a green compact; and a step o sintering the green compact at 900° C. or more and 1300° C. or less.

A composite magnetic material has a plurality of grains having a magnetic ferrite phase, grain boundaries surrounding the grains, and a plurality of nanoparticles disposed at the grain boundaries. The nanoparticles of the composite material are both magnetic and electrically insulating, having a magnetic flux density of greater than about 100 mT and an electrical resistivity of at least about 10.sup.8 Ohm-cm. Also provided is a method of making the composite material. The material is useful for making inductor cores of electronic devices.

The present invention relates to an apparatus and a method for manufacturing a soft magnetic composite using ultrasonic vibration and a soft magnetic composite manufactured using the ultrasonic vibration. More specifically, the present invention relates to the apparatus for manufacturing a soft magnetic composite using ultrasonic vibration including: a die that has a putting-in space as an open space in which a powder material is put; a punch set that is inserted into the putting-in space and presses the powder material; an ultrasonic vibration applying unit including ultrasonic vibrators which are arranged along a circumference of an outer die surface of the die and are provided to come into contact with the die; a main body that is positioned below the die and is formed to slide around the die toward an outer circumference; and a control unit that controls a frequency of the ultrasonic vibrators depending on a degree of pressure of the punch set, a method for manufacturing a soft magnetic composite using ultrasonic vibration, and a soft magnetic composite manufactured using the same.

A reactor is provided with a coil including a winding portion, and a magnetic core including an inner core portion to be arranged inside the winding portion and an outer core portion to be arranged outside the winding portion. The magnetic core includes a communication hole penetrating through the outer core portion and leading to the inner core portion, and a coupling shaft made of a composite material filled into the communication hole and coupling the inner core portion and the outer core portion. The composite material is obtained by dispersing a soft magnetic powder in a resin.

A reactor includes a coil having a wound portion and a magnetic core. The magnetic core includes a first core piece having a molded body of a composite material and a non-magnetic member, the molded body of the composite material contains a magnetic powder and a resin, the non-magnetic member is held by the molded body of the composite material such that the non-magnetic member and the molded body constitute a single piece, the non-magnetic member includes a base portion arranged along an outer peripheral surface of the molded body of the composite material and a protruding piece protruding from the base portion. The protruding piece is inserted into a region of the molded body of the composite material arranged inside of the wound portion so as to intersect an axial direction of the first core piece.

A reactor including a coil and a magnetic core, the magnetic core including a first inner core portion, a second inner core portion, a first outer core portion, and a second outer core portion. The reactor includes an inner resin portion and an outer resin portion, and the first outer core portion includes a first inner face that faces the coil, a first outer face on the opposite side to the first inner face, and an outward protruding portion protruding from the first outer face. When viewed from the first outer face side, the outer circumferential contour line of the outward protruding portion is located inside the outer circumferential contour line of the first outer face, and the end face of the outward protruding portion is exposed from the outer resin portion and is flush with the surface of the outer resin portion.

An inductive device and a manufacturing method thereof are provided. The inductive device includes a magnetic base, a coil structure, and a package structure. The magnetic base has an assembling surface, and an arrangement region is defined thereon. The coil structure is assembled to the magnetic base and includes a coil body, a first extending section, and a second extending section. The coil body has a though hole corresponding in position to the arrangement region, and the first and second extending sections both extend from the coil body toward the magnetic base and are wound on the magnetic base. The package structure covers the magnetic base and the coil structure. The package structure includes a magnetic molding main body, and a portion of the magnetic molding main body fills into the through hole of the coil body and is connected to the magnetic base.

A powder magnetic core manufacturing method includes: a first step of mixing a binder with a soft magnetic material powder containing Fe-M (M: Al or Cr)-based alloy particles on which an insulating layer is formed; a second step of filling a pressing die with a mixture obtained through the first step, subjecting the mixture to pressing to obtain a green compact, and slidingly demolding the green compact from the pressing die; a third step of processing the green compact after the second step and removing expansion deformed matter of the alloy particles present in a region of pressing flaws formed on a surface of the green compact during the slidingly demolding; and a fourth step of subjecting the green compact after the third step to heat treatment to oxidize surfaces of the Fe-M (M: Al or Cr)-based alloy particles at high temperature, so that the oxide phase is formed.

A coil component including a magnetic portion that includes metal particles and a resin material, a coil conductor embedded in the magnetic portion, and outer electrodes electrically connected to the coil conductor. Also, a protective layer containing Ti is disposed on the magnetic portion.